Bug #132369 for arXiv: Detection of LaTeX source file fails

Hello, I am having a problem with submitting one of my manuscripts to ArXiv. I like to put my \documentclass command outside of my main, TeX file. Thus, I created a 00README.XXX file to point the ArXiv build system to the correct main file. The problem is that since there is no \documentclass directive in the main file, the ArXiv build system assumes that my main file would be a plain TeX and not a LaTeX file. It then tries to build the document with plain TeX instead of LaTeX and fails. I would suggest to change the arXiv::FileGuess module to also recognize files which contain \begin, \usepackage, \section, \subsection, and \subsubsection as LaTeX files, instead of plain TeX files. I have attached a patch, which implements this functionality. I would be glad to see this change being included into the ArXiv build system. Kind Regards, Hannah Rittich